From ac2b6679222aae61d1ffda72b1ddab0199d7b68c Mon Sep 17 00:00:00 2001
From: Gergo Magyar <gergomagyar@icloud.com>
Date: Tue, 21 Apr 2026 20:42:24 +0100
Subject: [PATCH] =?UTF-8?q?feat(csharp-scope):=20parity=20Unit=205e=20?=
 =?UTF-8?q?=E2=80=94=20namespace-prefix=20bucket=20matching?=
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Closes 2 parity failures (12 → 10).

`languages/csharp/namespace-siblings.ts`: when matching accessible
namespaces against class buckets, also probe every dotted prefix.
`using static CrossFile.Models.UserFactory;` parses into the
importer's accessible-namespace set as the full type path, but the
matching bucket is keyed on the containing namespace
(`CrossFile.Models`). Walking back through the dotted segments
ensures the static-using importer sees the containing namespace's
sibling files' return-type bindings.

Legacy 175/175 green; 10 C# parity failures remain.
---
 .../languages/csharp/namespace-siblings.ts         | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/gitnexus/src/core/ingestion/languages/csharp/namespace-siblings.ts b/gitnexus/src/core/ingestion/languages/csharp/namespace-siblings.ts
index d434594fd..34cf4f7c3 100644
--- a/gitnexus/src/core/ingestion/languages/csharp/namespace-siblings.ts
+++ b/gitnexus/src/core/ingestion/languages/csharp/namespace-siblings.ts
@@ -160,7 +160,19 @@ export function populateCsharpNamespaceSiblings(
       }
     }
 
-    for (const nsName of accessibleNamespaces) {
+    // For each accessible namespace, also walk up the dotted path —
+    // `using static X.Y.Z;` targets a type, so the real namespace is
+    // `X.Y`. Both parse into `accessibleNamespaces` as-is; we probe
+    // the bucket map with every prefix.
+    const expandedNamespaces = new Set<string>(accessibleNamespaces);
+    for (const ns of accessibleNamespaces) {
+      const segments = ns.split('.');
+      for (let i = segments.length - 1; i > 0; i--) {
+        expandedNamespaces.add(segments.slice(0, i).join('.'));
+      }
+    }
+
+    for (const nsName of expandedNamespaces) {
       const bucket = buckets.get(nsName);
       if (bucket === undefined) continue;
       for (const scopeInfo of bucket.scopes) {